Apple tree rootstock named ‘G.814’

ABSTRACT

The present invention relates to a new and distinct variety of apple tree named ‘G.814’. ‘G.814’ is useful in that it can be propagated clonally and used as a rootstock or root system for apple trees as well as for interstems of apple trees. When used as a rootstock, ‘G.814’, is: dwarfing, induces scion precocity, is cold hardy, induces scion precocity, has a high yield efficiency, is tolerant to replant disease, and is resistant to: crown and root rot ( Phytophthora cactorum ), fire-blight ( Erwinia amylovora ), and powdery mildew. ‘G.814’ is susceptible to Apple Stem Grooving Virus (ASGV) and wooly apple aphid.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with United States government support under aUnited States Department of Agriculture-Agricultural Research StationCooperative Research and Development Agreement, Sponsor's ContractNumber 58-3K95-M-1031. The government has certain rights in theinvention.

Genus and species: Malus domestica×Malus robusta hybrid.

Variety denomination: ‘G.814’.

BACKGROUND OF THE INVENTION

I. Field and Utility Summary

The invention described herein is a new variety of apple tree, Malusdomestica×Malus robusta hybrid, hereinafter referred to as ‘G.814’. Thenew variety is useful as a dwarfing rootstock and is resistant to fireblight and crown rot. It is precocious and highly productive, and can beused as a rootstock and for interstems of apple trees.

II. Cultivation Summary

‘G.814’ originated from a planned cross in 1976 in Geneva, N.Y.

In the spring of 1976, pollen from a Malus robusta ‘Robusta 5’ appletree (not patented) was applied to emasculated flowers of a Malusdomestica ‘Ottawa 3’ apple tree (not patented) in Geneva, N.Y. In thefall of 1976, seeds resulting from this pollination were extracted frommature fruit derived from this cross. In the winter of 1976-77, theseeds were stratified and planted in large flats under conditionseffective to germinate seeds and obtain seedlings. When germinatedseedlings were about 2.5 cm tall they were inoculated with a mixture ofisolates of the fungus Phytophthora cactorum (the causal agent of crownand root rots). The flats were flooded to mid-hypocotyl level and keptat 23° C. for one week. Surviving seedlings were transplanted intoindividual pots.

In the summer of 1977, each of the transplanted seedlings was inoculatedwith approximately 10⁶ colony forming units of the Ea 273 strain of thefire blight bacterium Erwinia amylovora by inserting a 26-gaugehypodermic syringe needle into the shoot tip. The seedling designated as#814 was one of the survivors of this battery of inoculations from thesame cross. All the surviving plants were transplanted to a field inGeneva, N.Y. in the fall of 1977. The surviving plants were then allowedto grow side shoots for propagation and evaluation. In 1980, ‘G.814’ wasevaluated for rooting ability, lack of spine production, and low rootbrittleness in a layering bed (stool bed).

In 1984, three finished trees with ‘G.814’ rootstock were planted in afirst test orchard in Geneva, N.Y. with Malus domestica cv. ‘NorthernSpy’ (not patented) grafted onto this rootstock as the scion cultivar.This rootstock performed well (top 20% of many rootstocks tested) inthese first test trials. In 1991, this rootstock was advanced to elitestatus based on field performance and four trees were planted with Malusdomestica cv ‘Empire’ (not patented) for advanced evaluation. Thisplanting was evaluated for twelve years resulting in the classificationof ‘G.814’ in the dwarfing category similar to ‘Malling 26’ (notpatented) apple rootstock and the cumulative productivity in the top 10%of the planting.

In 1994, an additional experimental orchard was planted in Geneva, N.Y.It featured several trees of ‘G.814’ as the rootstocks with scions‘Mutsu’ (not patented), ‘Haralson’ (not patented), ‘Royalty’ (notpatented), and ‘Radiant’ (not patented) to test the productivity withdifferent scions. The tests resulted in acceptable performance withthese scions.

In the spring of 2002, ‘G.814’ and other experimental rootstocks wereplanted as finished trees with ‘Golden Delicious’ (not patented) scionin Geneva, N.Y. In 2003 and 2004 the orchard was spray inoculated, whilein bloom, with fire blight. All trees of ‘G.814’ survived, indicatinggood resistance of the rootstock in an orchard environment.

In February, 2002, several rootstock liners of ‘G.814’ were budded withApple Stem Grooving Virus (ASGV) (Capillovirus spp.) infected wood andafter the buds were healed the rootstocks were planted in a nursery inGeneva, N.Y. and monitored for survival and stunting. Measurements inAugust, 2002, showed that 50% of the plants had died and the survivingones were stunted. These results indicated that this rootstock issusceptible to ASGV.

In summer, 2007, twenty rootstock liners were inoculated with twodifferent strains of fire blight (ten liners per strain) in a greenhousein Geneva, N.Y. As a result, the apple rootstock ‘G.814’ was classifiedas resistant to all of the strains tested. Furthermore, ‘G.814’ wasobserved to be susceptible to wooly apple aphid, resistant to powderymildew, cold hardy, and tolerant of replant disease.

In the fall of 2005, the tree architecture of nursery trees was measuredon ‘G.814’ and found that it promotes higher number of feathers andmedium spreading habit on ‘Gala’ (U.S. Plant Pat. No. 03,637) scions.

III. Asexual Reproduction

Asexual reproduction of the ‘G.814’ apple rootstock has been achievedusing the traditional method of clonally propagating apple rootstocks.In particular, the original seedling of the ‘G.814’ apple rootstock wasplanted in Geneva, N.Y., and allowed to develop into a “mother plant.”The ‘G.814’ mother plant was then used to obtain rooted liners usingconventional layering procedures. The resulting liners were then plantedin a row to generate a layering stool bed (also referred to as the“mother stool bed”). The living tissues (i.e. leaves, stems, roots,buds, and spines) of the mother stool bed were observed to be identicalto secondary and tertiary stool bed plants. In addition to conventionallayering, the ‘G.814’ variety has been asexually reproduced in Geneva,N.Y., by root cuttings, by budding and grafting onto seedling and clonalrootstocks.

IV. Stability

Observations of trees from propagations in Geneva, N.Y. indicate thatall clonally propagated trees have proven true to type and identical inall appearances to the original tree.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to a new and distinct variety of appletree named ‘G.814’. ‘G.814’ is useful in that it can be propagatedclonally and used as a rootstock or root system for apple trees as wellas for interstems of apple trees.

When used as a rootstock, ‘G.814’ is: dwarfing, induces scion precocity,is cold hardy, induces scion precocity, has high yield efficiency, istolerant to replant disease, and is resistant to: crown and root rot(Phytophthora cactorum), fire-blight (Erwinia amylovora), and powderymildew (Podosphaera leucotricha). ‘G.814’ is susceptible to Apple StemGrooving Virus (ASGV, Capillovirus spp.) and wooly apple aphid (Eriosomalanigerum).

Characteristics of Parents, Comparators, and Distinguishing Features

Seed Parent—‘Ottawa 3’

The seed parent Malus domestica ‘Ottawa 3’ is a dwarfing rootstock;trees grown on this rootstock are 30 to 35 percent the size of astandard self-rooted seedling tree. ‘Ottawa 3’ is known to induce goodprecocity to the scion (induces early reproductive development in thescion) and has high yield efficiency. ‘Ottawa 3’ plants produce nospines, are fairly well anchored, are a very cold hardy rootstock, andhave resistance to crown and root rot caused by Phytophthora cactorum.However, ‘Ottawa 3’ is susceptible to the wooly apple aphid (Eriosomalanigerum) and to fire blight (Erwinia amylovora). ‘Ottawa 3’ has beencharacterized as susceptible to ASGV.

Pollen Parent—‘Robusta 5’

The pollen parent Malus robusta ‘Robusta 5’ is a non-dwarfing rootstock;trees on this rootstock are the same size as a standard self-rootedtree. ‘Robusta 5’ does not induce precocity to the scion and is nothighly yield efficient. Juvenile plants of ‘Robusta 5’ produce manyspines. ‘Robusta 5’ breaks buds very early in the spring and iswinter-hardy. It is resistant to powdery mildew (Podosphaeraleucotricha) and fire blight, and is immune to the wooly apple aphid.‘Robusta 5’ on its own roots has a spreading architectural habit.Further, ‘Robusta 5’ has shown tolerance to the replant disease complex.

Comparison of ‘G.814’ with ‘Ottawa 3’

‘G.814’ is distinguished from ‘Ottawa 3’ in that ‘G.814’ is resistant tofire blight, whereas ‘Ottawa 3’ is not resistant to fire blight.

‘G.814’ is similar to ‘Ottawa 3’ in that they share dwarfing properties,induce precocity to the scion, and are: yield efficient, cold-hardy,susceptible to ASGV, and resistant to crown and root rot caused byPhytophthora cactorum.

Comparison of ‘G.814’ with ‘Robusta 5’

‘G.814’ is distinguished from ‘Robusta 5’ in that ‘G.814’ is: a dwarfingrootstock, induces scion precocity, and is highly yield efficient, while‘Robusta 5’ is not a dwarfing rootstock, does not induce scionprecocity, and is not highly yield efficient.

‘G.814’ is similar to ‘Robusta 5’, in that they share these properties:cold hardiness, resistance to fire blight, resistance to wooly appleaphid, resistance to powdery mildew, and tolerance of replant disease.

Comparison with ‘Malling 26’ (‘M.26’)

‘G.814’ is distinguished from ‘M.26’ in that ‘G.814’ is resistant tofire blight and tolerant of replant disease, whereas ‘M.26’ is notresistant to fire blight or tolerant of replant disease. ‘G.814’exhibits finer, more branched root system than ‘M.26’ roots, resultingin higher exploration of the soil profile.

‘G.814’ is similar to ‘M.26’ in that they share these properties:dwarfing, scion precocity induction, and high yield efficiency.

Distinguishing Characteristics of ‘G.814’

The ‘G.814’ apple tree is distinguished from ‘Robusta 5’, ‘Ottawa 3’,and ‘M.26’ in that ‘G.814’ has this combination of characteristics whenused as a rootstock: dwarfing, induces scion precocity, high yieldefficiency, fire-blight resistance, and replant disease tolerance.

BRIEF DESCRIPTION OF THE FIGURES

New apple tree rootstock ‘G.814’ is illustrated by the accompanyingphotographs. The ages of the trees depicted in the photographs are notedbelow. The colors shown are as true as can be reasonably obtained byconventional photographic procedures.

FIG. 1 is a photograph of 2-year-old ‘G.814’ liners in the nursery.

FIG. 2 is a photograph of live plants of 4-6 years in age in apropagation bed.

FIG. 3 is a photograph of leaves on the apex of a shoot of a 15-year-oldplant.

FIG. 4 is a photograph of a two-year-old shoot with leaf spurs andleaves.

FIG. 5 is a photograph of bark and buds on a one-year shoot.

FIG. 6 is a photograph of fruit on a 15-year-old tree.

FIG. 7 is a photograph of fruit size, shape, and sections on a measuringboard. Fruit is from a 15-year-old tree.

FIG. 8 is a photograph of mature leaf upper side, size, and shape on ameasuring board. Leaves are from a 15-year-old tree.

FIG. 9 is a photograph of fine or branched root production in apropagation bed of 4-6 years in age.

FIG. 10 is a photograph of a mature leaf lower side. Leaves are from a15-year-old tree.

DETAILED BOTANICAL DESCRIPTION OF THE INVENTION

The following description of apple tree rootstock ‘G.814’ containsreferences to color names taken from The Royal Horticultural SocietyColour Chart (R.H.S.), 2001 edition. Botanical descriptions follow theManual of Cultivated Plants (Bailey, 1949).

-   Tree:    -   -   Habit.—Low vigor bush. A self-rooted tree of ‘G.814’ is a            small shrub typically standing about 1.2-1.5 meters tall by            about 1.5 meters wide when nine-years-old. There is no            single dominant trunk. Instead there are few shoots arising            from the crown. Some suckers (new shoots emerging from below            ground) are produced. Liners planted in the nursery stop            apical growth mid season. Root systems are very branched.            Liners are straight with few spines. The apical bud in these            plants is pubescent Greyed-Green (RHS 191D).        -   Productivity.—In an elite rootstock trial performed in            Geneva, N.Y., the ‘G.814’ rootstock received the cultivar            ‘Empire’ (Malus domestica) as the scion and was compared to            the Malus domestica check rootstocks ‘M.9’ ‘EMLA’ (not            patented) and ‘M.26’. ‘G.814’ was shown to have            statistically higher (p≦0.05) yield efficiency (kg yield/cm2            trunk cross sectional area) than all the check rootstocks.        -   Precocity.—Scion cultivars budded on ‘G.814’ exhibit the            similar precocity as those budded on ‘M.9’.        -   Fertility (fecundity).—The ‘G.814’ plant produces flowers            and fruits regularly.-   Dormant shoots (buds and bark):    -   -   Color.—Greyed-Red (RHS 178A) where exposed to full sunlight            grading to Greyed-Orange (RHS 173B) with diminished light            exposure.        -   Texture.—Very light pubescence which gradually disappears in            older tissues. Size: 30-60 cm long; few spines.        -   Axillary buds.—Size: 2-3 mm long and 3 mm wide with little            pubescence. Shape: Obtuse, sessile, somewhat appressed and            flattened. Texture: Some pubescence.        -   Bark on three-year-old shoots.—Color: Greyed-Green (RHS            197A). Lenticels: Color: Greyed-Orange (RHS 163B). Size:            0.3-0.4 mm in diameter. Quantity: 1-2 lenticels per cm².-   Leaves:    -   -   Mature leaves.—Leaf arrangement: Alternate. Shape: Simple,            recurved, oblong-ovate. Size: Length: 85 mm. Width: 45 mm at            the widest point. Laminae: Somewhat wavy. Apex: Acuminate.            Base: Nearly symmetrical rounded. Margin: Acutely serrated,            with about 5 serrations per cm. Upper surface: Color: Green            (RHS 132B). Texture: Glabrous and translucent. Glossiness:            Medium. Lower surface: Color: Greyed-Green (RHS 191B).            Texture: Somewhat pubescent. Glossiness: Absent. Venation:            Netted. Leaf poise: 355°-455° from the shoot, depending on            shoot orientation. Stipules: Color: Green (RHS 132B).            Length: 8 mm. Width: 2 mm. Petioles: Diameter: 2 mm. Color:            Gradation of Green (RHS 140A) to Greyed-Red (RHS 179A)            depending on low or high exposure to light. Texture: Smooth.            Length: 1.7 cm on average.-   Flowers:    -   -   Habit.—Flowers borne on spurs, shoot terminals, and from            lateral buds on growth from previous season.        -   Flower diameter.—40 mm.        -   Fragrance.—None.        -   Buds.—Location: Located on spurs and terminals; are mixed,            typically producing a truss of 5 to 6 flowers and one bourse            shoot. Number: 5-6 flowers on bourse shoot. 2-4 in mid            shoot. Shape: Lateral buds are obtuse, sessile and somewhat            appressed. Size: Length: 4 mm. Width: 3 mm. Habit: Buds near            the base of the shoot of the previous season usually produce            3 to 5 flowers and a single short shoot; mid-shoot buds may            have 2-4 flowers; and more distal buds are usually            vegetative.        -   Petals.—Arrangement: Intermediate. Texture: Top: Venated.            Bottom: Venated.        -   Pedicel.—Length: 28 mm. Diameter: 1.5 mm. Color:            Yellow-Green (RHS 143A).        -   Size.—Length: 25 mm. Width: 18 mm. Shape: Spatulate. Apex:            Obtuse. Margin: Smooth. Texture: Smooth. Color: Closed            petals: Red (RHS 54A). Open petals: White (RHS 155D) with            Red (RHS 54A) striations in some of the petals.        -   Reproductive organs.—Pollen: Amount: medium. Color:            Yellow-Orange (RHS 14C). Pistils: Number: 5. Length: 6 mm.            Color: Yellow-white (RHS 145B). Stigma: Shape: Double            kidney. Color: Yellow-White (RHS 158C). Ovary size: 5 mm in            height and 5 mm in width. Ovary color (external): Red (RHS            46B). Stamens: Length: 4 mm. Color: White (RHS 155D).            Another color: Yellow-Brown (RHS 167D). Anther: Length:            1.5 mm. Filament height: 8 mm. Shape: Indented kidney.            Color: Yellow-Orange (RHS 14C) with middle Yellow-Orange            (RHS 22A).-   Fruit:    -   -   Mature fruit.—Size: Height: 30-35 mm. Diameter: 30-35 mm.            Shape: Round Obloid. Color: Partial Red-skin (RHS 45A) with            Yellow-Orange (RHS 23B) blush undertones depending on the            exposure to the sun. Sepals: Sometimes persisting on a            variable protruding calyx. Flesh: Taste: Astringent (not            meant for consumption). Color: Yellow-Orange (RHS 21C) with            Red (RHS 42B) bleed through from the skin in mature fruits.            Seed: Texture: Glossy. Color: Greyed-Red (RHS 178A),            translucent. Shape: Tear drop shape. Size: Length: 50-60 mm.            Diameter: 25-35 mm at the widest point. Number: Generally            5-7 seed per fruit.-   Disease resistance: As described above, the ‘G.814’ rootstock of the    present invention exhibits resistance to fire blight. The    percent-lesion measured after inoculation of potted liners in the    greenhouse using four different strains of E. amylovora was    negligible for all strains tested in Geneva, N.Y. The ‘G.814’    rootstock, having survived the inoculation with crown and root rot,    is also considered resistant to crown and root rots caused by    Phytophthora cactorum. ‘G.814’ is susceptible to ASGV and wooly    apple aphid.

We claim:
 1. A new and distinct variety of apple tree named ‘G.814’ asherein described and illustrated.